rxjs

const { range, from, of, Observable } = require("rxjs");

const { map, filter, concat } = require("rxjs/operators");

const fs = require("fs");

// range(1, 200)

// .pipe(

// filter(x => x % 2 === 1),

// map(x => x + x)

// )

// .subscribe(x => console.log(x));

function delay() {

return new Promise(function(resolve, reject) {

setTimeout(function() {

// resolve("delayed");

resolve();

}, 1000);

});

}

function writeFile() {

return new Promise(function(resolve, reject) {

var content = '[{ "name": "LuiBei", "birth": "161", "death": "223", "hometown": "탁현" }, { "name": "GuanYu", "birth": "161", "death": "219", "hometown": "상평" }, { "name": "ZhangFei", "birth": "165", "death": "221", "hometown": "탁현" }]';

fs.writeFile("0001.txt", content, function(err) {

if (err) {

reject(err);

} else {

// resolve("saved");

resolve();

}

});

});

}

function readFile() {

return new Promise(function(resolve, reject) {

fs.readFile("0001.txt", "utf-8", function(err, data) {

if (err) {

reject(err);

} else {

resolve(data);

}

});

});

}

function myJsonParser(person) {

try {

return JSON.parse(person);

} catch (e) {

console.log(e);

return "aa";

}

}

const delay$ = from(delay());

const writeFile$ = from(writeFile());

const readFile$ = from(readFile());

const myStream$ = delay$

.pipe(concat(writeFile$))

.pipe(concat(readFile$))

.pipe(filter(res => res))

.pipe(map(person => JSON.parse(person)))

.pipe(arr => {

console.log("arr : " + JSON.stringify(arr));

return Observable.create(function(oberser) {

arr.forEach(item => {

console.log("item : " + JSON.stringify(item));

oberser.next(item);

});

});

});

// delay$.subscribe(result => console.log(result));

//writeFile$.subscribe(result => console.log(result));

// console.log(typeof concat);

myStream$.subscribe(result => console.log(result));

// const sourceOne = of(1, 2, 3);

// const sourceTwo = of(4, 5, 6);

// const example = sourceOne.pipe(concat(sourceTwo));

// const subscribe = example.subscribe(val => console.log(" Example Basic Concat : " + val));